Linux-kselftest-mirror February 2023

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187 discussions

[PATCH v9 0/3] Implement IOCTL to get and/or the clear info about PTEs

by Muhammad Usama Anjum

*Changes in v9:* - Correct fault resolution for userfaultfd wp async - Fix build warnings and errors which were happening on some configs - Simplify pagemap ioctl's code *Changes in v8:* - Update uffd async wp implementation - Improve PAGEMAP_IOCTL implementation *Changes in v7:* - Add uffd wp async - Update the IOCTL to use uffd under the hood instead of soft-dirty flags Hello, Note: Soft-dirty pages and pages which have been written-to are synonyms. As kernel already has soft-dirty feature inside which we have given up to use, we are using written-to terminology while using UFFD async WP under the hood. This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear the info about page table entries. The following operations are supported in this ioctl: - Get the information if the pages have been written-to (PAGE_IS_WRITTEN), file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped (PAGE_IS_SWAPPED). - Write-protect the pages (PAGEMAP_WP_ENGAGE) to start finding which pages have been written-to. - Find pages which have been written-to and write protect the pages (atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE) It is possible to find and clear soft-dirty pages entirely in userspace. But it isn't efficient: - The mprotect and SIGSEGV handler for bookkeeping - The userfaultfd wp (synchronous) with the handler for bookkeeping Some benchmarks can be seen here[1]. This series adds features that weren't present earlier: - There is no atomic get soft-dirty/Written-to status and clear present in the kernel. - The pages which have been written-to can not be found in accurate way. (Kernel's soft-dirty PTE bit + sof_dirty VMA bit shows more soft-dirty pages than there actually are.) Historically, soft-dirty PTE bit tracking has been used in the CRIU project. The procfs interface is enough for finding the soft-dirty bit status and clearing the soft-dirty bit of all the pages of a process. We have the use case where we need to track the soft-dirty PTE bit for only specific pages on-demand. We need this tracking and clear mechanism of a region of memory while the process is running to emulate the getWriteWatch() syscall of Windows. *(Moved to using UFFD instead of soft-dirtyi feature to find pages which have been written-to from v7 patch series)*: Stop using the soft-dirty flags for finding which pages have been written to. It is too delicate and wrong as it shows more soft-dirty pages than the actual soft-dirty pages. There is no interest in correcting it [2][3] as this is how the feature was written years ago. It shouldn't be updated to changed behaviour. Peter Xu has suggested using the async version of the UFFD WP [4] as it is based inherently on the PTEs. So in this patch series, I've added a new mode to the UFFD which is asynchronous version of the write protect. When this variant of the UFFD WP is used, the page faults are resolved automatically by the kernel. The pages which have been written-to can be found by reading pagemap file (!PM_UFFD_WP). This feature can be used successfully to find which pages have been written to from the time the pages were write protected. This works just like the soft-dirty flag without showing any extra pages which aren't soft-dirty in reality. The information related to pages if the page is file mapped, present and swapped is required for the CRIU project [5][6]. The addition of the required mask, any mask, excluded mask and return masks are also required for the CRIU project [5]. The IOCTL returns the addresses of the pages which match the specific masks. The page addresses are returned in struct page_region in a compact form. The max_pages is needed to support a use case where user only wants to get a specific number of pages. So there is no need to find all the pages of interest in the range when max_pages is specified. The IOCTL returns when the maximum number of the pages are found. The max_pages is optional. If max_pages is specified, it must be equal or greater than the vec_size. This restriction is needed to handle worse case when one page_region only contains info of one page and it cannot be compacted. This is needed to emulate the Windows getWriteWatch() syscall. The patch series include the detailed selftest which can be used as an example for the uffd async wp test and PAGEMAP_IOCTL. It shows the interface usages as well. [1] https://lore.kernel.org/lkml/54d4c322-cd6e-eefd-b161-2af2b56aae24@collabora… [2] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.… [3] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.… [4] https://lore.kernel.org/all/Y6Hc2d+7eTKs7AiH@x1n [5] https://lore.kernel.org/all/YyiDg79flhWoMDZB@gmail.com/ [6] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com/ Regards, Muhammad Usama Anjum Muhammad Usama Anjum (3): userfaultfd: Add UFFD WP Async support fs/proc/task_mmu: Implement IOCTL to get and/or the clear info about PTEs selftests: vm: add pagemap ioctl tests fs/proc/task_mmu.c | 290 +++++++ fs/userfaultfd.c | 11 + include/linux/userfaultfd_k.h | 6 + include/uapi/linux/fs.h | 50 ++ include/uapi/linux/userfaultfd.h | 8 +- mm/memory.c | 23 +- tools/include/uapi/linux/fs.h | 50 ++ tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 5 +- tools/testing/selftests/vm/pagemap_ioctl.c | 881 +++++++++++++++++++++ 10 files changed, 1319 insertions(+), 6 deletions(-) create mode 100644 tools/testing/selftests/vm/pagemap_ioctl.c -- 2.30.2

1 year, 2 months

Faktoring

by "Szczepan Kiełbasa"

Dzień dobry, rozważali Państwo wybór finansowania, które spełni potrzeby firmy, zapewniając natychmiastowy dostęp do gotówki, bez zbędnych przestojów? Przygotowaliśmy rozwiązania faktoringowe dopasowane do Państwa branży i wielkości firmy, dzięki którym, nie muszą Państwo martwić się o niewypłacalność kontrahentów, ponieważ transakcje są zabezpieczone i posiadają gwarancję spłaty. Chcą Państwo przeanalizować dostępne opcje? Pozdrawiam Szczepan Kiełbasa

1 year, 2 months

[PATCH] selftests: KVM: Replace optarg with arg in guest_modes_cmdline

by shahuang＠redhat.com

From: Shaoqin Huang <shahuang(a)redhat.com> The parameter arg in guest_modes_cmdline not being used now, and the optarg should be replaced with arg in guest_modes_cmdline. Signed-off-by: Shaoqin Huang <shahuang(a)redhat.com> --- tools/testing/selftests/kvm/lib/guest_modes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/lib/guest_modes.c b/tools/testing/selftests/kvm/lib/guest_modes.c index 99a575bbbc52..1f2dca4520ab 100644 --- a/tools/testing/selftests/kvm/lib/guest_modes.c +++ b/tools/testing/selftests/kvm/lib/guest_modes.c @@ -127,7 +127,7 @@ void guest_modes_cmdline(const char *arg) mode_selected = true; } - mode = strtoul(optarg, NULL, 10); + mode = strtoul(arg, NULL, 10); TEST_ASSERT(mode < NUM_VM_MODES, "Guest mode ID %d too big", mode); guest_modes[mode].enabled = true; } -- 2.39.0

1 year, 2 months

[RFC PATCH 0/2] xapic: make sure x2APIC -> xapic transition correctly

by Emanuele Giuseppe Esposito

The root cause is kvm_lapic_set_base() failing to handle x2APIC -> xapic ID switch, which is addressed by patch 1. Patch 2 provides a selftest to verify this behavior. This serie is an RFC because I think that commit ef40757743b47 already tries to fix one such effect of the error made in kvm_lapic_set_base, but I am not sure how such error described in the commit message is triggered, nor how to reproduce it using a selftest. I don't think one can enable/disable x2APIC using KVM_SET_LAPIC, and kvm_lapic_set_base() in kvm_apic_set_state() just takes care of updating apic->base_address, since value == old_value. The test in patch 2 fails with the fix in ef40757743b47. Thank you, Emanuele Emanuele Giuseppe Esposito (2): KVM: x86: update APIC_ID also when disabling x2APIC in kvm_lapic_set_base KVM: selftests: APIC_ID must be correctly updated when disabling x2apic arch/x86/kvm/lapic.c | 8 ++- .../selftests/kvm/x86_64/xapic_state_test.c | 64 +++++++++++++++++++ 2 files changed, 70 insertions(+), 2 deletions(-) -- 2.31.1

1 year, 2 months

[PATCH] kselftest/arm64: Don't require FA64 for streaming SVE tests

by Mark Brown

During early development a dependedncy was added on having FA64 available so we could use the full FPSIMD register set in the signal handler. Subsequently the ABI was finialised so the handler is run with streaming mode disabled meaning this is redundant but the dependency was never removed, do so now. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/arm64/signal/testcases/ssve_regs.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c b/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c index d0a178945b1a..f0985da7936e 100644 --- a/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c +++ b/tools/testing/selftests/arm64/signal/testcases/ssve_regs.c @@ -116,12 +116,7 @@ static int sme_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc) struct tdescr tde = { .name = "Streaming SVE registers", .descr = "Check that we get the right Streaming SVE registers reported", - /* - * We shouldn't require FA64 but things like memset() used in the - * helpers might use unsupported instructions so for now disable - * the test unless we've got the full instruction set. - */ - .feats_required = FEAT_SME | FEAT_SME_FA64, + .feats_required = FEAT_SME, .timeout = 3, .init = sme_get_vls, .run = sme_regs, --- base-commit: b7bfaa761d760e72a969d116517eaa12e404c262 change-id: 20230131-arm64-kselfetest-ssve-fa64-cec2031da43f Best regards, -- Mark Brown <broonie(a)kernel.org>

1 year, 2 months

[PATCH 0/2] kselftest/arm64: Fix enumeration of SME VLs on systems without VL 128

by Mark Brown

These two patches fix a repeated error with the way we enumerate SME VLs, the code for which is cut'n'pasted into each test. It's in two patches because the first applies to Linus' tree and the second covers a new test added in -next, even if they're both applied for -next now this should help with backporting. It would be good to factor this code out but that's a separate issue, I'll tackle that for the next release (along with the general fun with the build system in these tests). Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Mark Brown (2): kselftest/arm64: Fix enumeration of systems without 128 bit SME kselftest/arm64: Fix enumeration of systems without 128 bit SME for SSVE+ZA tools/testing/selftests/arm64/signal/testcases/ssve_regs.c | 4 ++++ tools/testing/selftests/arm64/signal/testcases/ssve_za_regs.c | 4 ++++ tools/testing/selftests/arm64/signal/testcases/za_regs.c | 4 ++++ 3 files changed, 12 insertions(+) --- base-commit: 8154ffb7a51882c00730952ed21d80ed76f165d7 change-id: 20230131-arm64-kselftest-sig-sme-no-128-8dd219305a32 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 year, 2 months

[PATCH 0/9] use canonical ftrace path whenever possible

by Ross Zwisler

The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing There are many places where this older debugfs path is still used in code comments, selftests, examples and tools, so let's update them to avoid confusion. I've broken up the series as best I could by maintainer or directory, and I've only sent people the patches that I think they care about to avoid spamming everyone. Ross Zwisler (9): tracing: always use canonical ftrace path bpf: use canonical ftrace path selftests/bpf: use canonical ftrace path perf docs: use canonical ftrace path tools/power: use canonical ftrace path selftests: use canonical ftrace path tools/virtio: use canonical ftrace path leaking_addresses: also skip canonical ftrace path tools/kvm_stat: use canonical ftrace path include/linux/kernel.h | 2 +- include/linux/tracepoint.h | 4 ++-- include/uapi/linux/bpf.h | 8 ++++---- kernel/trace/Kconfig | 20 +++++++++---------- kernel/trace/kprobe_event_gen_test.c | 2 +- kernel/trace/ring_buffer.c | 2 +- kernel/trace/synth_event_gen_test.c | 2 +- kernel/trace/trace.c | 2 +- samples/bpf/cpustat_kern.c | 4 ++-- samples/bpf/hbm.c | 4 ++-- samples/bpf/ibumad_kern.c | 4 ++-- samples/bpf/lwt_len_hist.sh | 2 +- samples/bpf/offwaketime_kern.c | 2 +- samples/bpf/task_fd_query_user.c | 4 ++-- samples/bpf/test_lwt_bpf.sh | 2 +- samples/bpf/test_overhead_tp_kern.c | 4 ++-- samples/user_events/example.c | 4 ++-- scripts/leaking_addresses.pl | 1 + scripts/tracing/draw_functrace.py | 6 +++--- scripts/tracing/ftrace-bisect.sh | 4 ++-- tools/include/uapi/linux/bpf.h | 8 ++++---- tools/kvm/kvm_stat/kvm_stat | 2 +- tools/lib/api/fs/tracing_path.c | 4 ++-- tools/lib/traceevent/event-parse.c | 8 ++++---- tools/perf/Documentation/perf-list.txt | 2 +- tools/perf/Documentation/perf-script-perl.txt | 2 +- .../perf/Documentation/perf-script-python.txt | 4 ++-- tools/power/pm-graph/sleepgraph.py | 4 ++-- .../x86/amd_pstate_tracer/amd_pstate_trace.py | 4 ++-- .../intel_pstate_tracer.py | 10 +++++----- .../selftests/bpf/get_cgroup_id_user.c | 2 +- .../bpf/prog_tests/kprobe_multi_test.c | 2 +- .../bpf/prog_tests/task_fd_query_tp.c | 2 +- .../bpf/prog_tests/tp_attach_query.c | 2 +- .../selftests/bpf/prog_tests/trace_printk.c | 2 +- .../selftests/bpf/prog_tests/trace_vprintk.c | 2 +- .../selftests/bpf/progs/test_stacktrace_map.c | 2 +- .../selftests/bpf/progs/test_tracepoint.c | 2 +- tools/testing/selftests/bpf/test_ftrace.sh | 2 +- tools/testing/selftests/bpf/test_tunnel.sh | 8 ++++---- tools/testing/selftests/bpf/trace_helpers.c | 4 ++-- .../testing/selftests/user_events/dyn_test.c | 2 +- .../selftests/user_events/ftrace_test.c | 10 +++++----- .../testing/selftests/user_events/perf_test.c | 8 ++++---- tools/testing/selftests/vm/protection_keys.c | 4 ++-- tools/tracing/latency/latency-collector.c | 2 +- tools/virtio/virtio-trace/README | 2 +- tools/virtio/virtio-trace/trace-agent.c | 2 +- 48 files changed, 96 insertions(+), 95 deletions(-) -- 2.39.1.456.gfc5497dd1b-goog

1 year, 2 months

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Linux-kselftest-mirror February 2023